What sort of hob is it? We have an induction hob, we just wipe it over each evening. Occasionally I'll use glass cleaner on it but nothing g else. You can't get food burned onto an induction hob though.

When we had a ceramic hob we used Astonish from Lakeland for really stubborn stains.

I second hobbrite. Pour boiling water on it, let it soak until cooled then wipe off. Then smother it in hobbrite, leave it for five minutes then scrub off. It you have a flat / glass hob you can use a glass scraper to get the stubborn bits off. Then hobbrite again, wipe off and then dry to a shine with a towel.

Use hobbrite regularly, it conditions the surface to prevent stains.

If it's really greasy, use cilit bang (the grease version, not the lime scale one).

Don't use John Lewis' spray version of hobbrite - my hob has never been the same since...